drivers/android/binder_alloc.c

   1 /* binder_alloc.c
   2  *
   3  * Android IPC Subsystem
   4  *
   5  * Copyright (C) 2007-2017 Google, Inc.
   6  *
   7  * This software is licensed under the terms of the GNU General Public
   8  * License version 2, as published by the Free Software Foundation, and
   9  * may be copied, distributed, and modified under those terms.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  * GNU General Public License for more details.
  15  *
  16  */
  17
  18 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  19
  20 #include <linux/list.h>
  21 #include <linux/sched/mm.h>
  22 #include <linux/module.h>
  23 #include <linux/rtmutex.h>
  24 #include <linux/rbtree.h>
  25 #include <linux/seq_file.h>
  26 #include <linux/vmalloc.h>
  27 #include <linux/slab.h>
  28 #include <linux/sched.h>
  29 #include <linux/list_lru.h>
  30 #include <linux/ratelimit.h>
  31 #include <asm/cacheflush.h>
  32 #include "binder_alloc.h"
  33 #include "binder_trace.h"
  34
  35 struct list_lru binder_alloc_lru;
  36
  37 static DEFINE_MUTEX(binder_alloc_mmap_lock);
  38
  39 enum {
  40         BINDER_DEBUG_USER_ERROR             = 1U << 0,
  41         BINDER_DEBUG_OPEN_CLOSE             = 1U << 1,
  42         BINDER_DEBUG_BUFFER_ALLOC           = 1U << 2,
  43         BINDER_DEBUG_BUFFER_ALLOC_ASYNC     = 1U << 3,
  44 };
  45 static uint32_t binder_alloc_debug_mask = BINDER_DEBUG_USER_ERROR;
  46
  47 module_param_named(debug_mask, binder_alloc_debug_mask,
  48                    uint, 0644);
  49
  50 #define binder_alloc_debug(mask, x...) \
  51         do { \
  52                 if (binder_alloc_debug_mask & mask) \
  53                         pr_info_ratelimited(x); \
  54         } while (0)
  55
  56 static struct binder_buffer *binder_buffer_next(struct binder_buffer *buffer)
  57 {
  58         return list_entry(buffer->entry.next, struct binder_buffer, entry);
  59 }
  60
  61 static struct binder_buffer *binder_buffer_prev(struct binder_buffer *buffer)
  62 {
  63         return list_entry(buffer->entry.prev, struct binder_buffer, entry);
  64 }
  65
  66 static size_t binder_alloc_buffer_size(struct binder_alloc *alloc,
  67                                        struct binder_buffer *buffer)
  68 {
  69         if (list_is_last(&buffer->entry, &alloc->buffers))
  70                 return (u8 *)alloc->buffer +
  71                         alloc->buffer_size - (u8 *)buffer->data;
  72         return (u8 *)binder_buffer_next(buffer)->data - (u8 *)buffer->data;
  73 }
  74
  75 static void binder_insert_free_buffer(struct binder_alloc *alloc,
  76                                       struct binder_buffer *new_buffer)
  77 {
  78         struct rb_node **p = &alloc->free_buffers.rb_node;
  79         struct rb_node *parent = NULL;
  80         struct binder_buffer *buffer;
  81         size_t buffer_size;
  82         size_t new_buffer_size;
  83
  84         BUG_ON(!new_buffer->free);
  85
  86         new_buffer_size = binder_alloc_buffer_size(alloc, new_buffer);
  87
  88         binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
  89                      "%d: add free buffer, size %zd, at %pK\n",
  90                       alloc->pid, new_buffer_size, new_buffer);
  91
  92         while (*p) {
  93                 parent = *p;
  94                 buffer = rb_entry(parent, struct binder_buffer, rb_node);
  95                 BUG_ON(!buffer->free);
  96
  97                 buffer_size = binder_alloc_buffer_size(alloc, buffer);
  98
  99                 if (new_buffer_size < buffer_size)
 100                         p = &parent->rb_left;
 101                 else
 102                         p = &parent->rb_right;
 103         }
 104         rb_link_node(&new_buffer->rb_node, parent, p);
 105         rb_insert_color(&new_buffer->rb_node, &alloc->free_buffers);
 106 }
 107
 108 static void binder_insert_allocated_buffer_locked(
 109                 struct binder_alloc *alloc, struct binder_buffer *new_buffer)
 110 {
 111         struct rb_node **p = &alloc->allocated_buffers.rb_node;
 112         struct rb_node *parent = NULL;
 113         struct binder_buffer *buffer;
 114
 115         BUG_ON(new_buffer->free);
 116
 117         while (*p) {
 118                 parent = *p;
 119                 buffer = rb_entry(parent, struct binder_buffer, rb_node);
 120                 BUG_ON(buffer->free);
 121
 122                 if (new_buffer->data < buffer->data)
 123                         p = &parent->rb_left;
 124                 else if (new_buffer->data > buffer->data)
 125                         p = &parent->rb_right;
 126                 else
 127                         BUG();
 128         }
 129         rb_link_node(&new_buffer->rb_node, parent, p);
 130         rb_insert_color(&new_buffer->rb_node, &alloc->allocated_buffers);
 131 }
 132
 133 static struct binder_buffer *binder_alloc_prepare_to_free_locked(
 134                 struct binder_alloc *alloc,
 135                 uintptr_t user_ptr)
 136 {
 137         struct rb_node *n = alloc->allocated_buffers.rb_node;
 138         struct binder_buffer *buffer;
 139         void *kern_ptr;
 140
 141         kern_ptr = (void *)(user_ptr - alloc->user_buffer_offset);
 142
 143         while (n) {
 144                 buffer = rb_entry(n, struct binder_buffer, rb_node);
 145                 BUG_ON(buffer->free);
 146
 147                 if (kern_ptr < buffer->data)
 148                         n = n->rb_left;
 149                 else if (kern_ptr > buffer->data)
 150                         n = n->rb_right;
 151                 else {
 152                         /*
 153                          * Guard against user threads attempting to
 154                          * free the buffer twice
 155                          */
 156                         if (buffer->free_in_progress) {
 157                                 binder_alloc_debug(BINDER_DEBUG_USER_ERROR,
 158                                                    "%d:%d FREE_BUFFER u%016llx user freed buffer twice\n",
 159                                                    alloc->pid, current->pid,
 160                                                    (u64)user_ptr);
 161                                 return NULL;
 162                         }
 163                         buffer->free_in_progress = 1;
 164                         return buffer;
 165                 }
 166         }
 167         return NULL;
 168 }
 169
 170 /**
 171  * binder_alloc_buffer_lookup() - get buffer given user ptr
 172  * @alloc:      binder_alloc for this proc
 173  * @user_ptr:   User pointer to buffer data
 174  *
 175  * Validate userspace pointer to buffer data and return buffer corresponding to
 176  * that user pointer. Search the rb tree for buffer that matches user data
 177  * pointer.
 178  *
 179  * Return:      Pointer to buffer or NULL
 180  */
 181 struct binder_buffer *binder_alloc_prepare_to_free(struct binder_alloc *alloc,
 182                                                    uintptr_t user_ptr)
 183 {
 184         struct binder_buffer *buffer;
 185
 186         mutex_lock(&alloc->mutex);
 187         buffer = binder_alloc_prepare_to_free_locked(alloc, user_ptr);
 188         mutex_unlock(&alloc->mutex);
 189         return buffer;
 190 }
 191
 192 static int binder_update_page_range(struct binder_alloc *alloc, int allocate,
 193                                     void *start, void *end)
 194 {
 195         void *page_addr;
 196         unsigned long user_page_addr;
 197         struct binder_lru_page *page;
 198         struct vm_area_struct *vma = NULL;
 199         struct mm_struct *mm = NULL;
 200         bool need_mm = false;
 201
 202         binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
 203                      "%d: %s pages %pK-%pK\n", alloc->pid,
 204                      allocate ? "allocate" : "free", start, end);
 205
 206         if (end <= start)
 207                 return 0;
 208
 209         trace_binder_update_page_range(alloc, allocate, start, end);
 210
 211         if (allocate == 0)
 212                 goto free_range;
 213
 214         for (page_addr = start; page_addr < end; page_addr += PAGE_SIZE) {
 215                 page = &alloc->pages[(page_addr - alloc->buffer) / PAGE_SIZE];
 216                 if (!page->page_ptr) {
 217                         need_mm = true;
 218                         break;
 219                 }
 220         }
 221
 222         if (need_mm && mmget_not_zero(alloc->vma_vm_mm))
 223                 mm = alloc->vma_vm_mm;
 224
 225         if (mm) {
 226                 down_read(&mm->mmap_sem);
 227                 vma = alloc->vma;
 228         }
 229
 230         if (!vma && need_mm) {
 231                 binder_alloc_debug(BINDER_DEBUG_USER_ERROR,
 232                                    "%d: binder_alloc_buf failed to map pages in userspace, no vma\n",
 233                                    alloc->pid);
 234                 goto err_no_vma;
 235         }
 236
 237         for (page_addr = start; page_addr < end; page_addr += PAGE_SIZE) {
 238                 int ret;
 239                 bool on_lru;
 240                 size_t index;
 241
 242                 index = (page_addr - alloc->buffer) / PAGE_SIZE;
 243                 page = &alloc->pages[index];
 244
 245                 if (page->page_ptr) {
 246                         trace_binder_alloc_lru_start(alloc, index);
 247
 248                         on_lru = list_lru_del(&binder_alloc_lru, &page->lru);
 249                         WARN_ON(!on_lru);
 250
 251                         trace_binder_alloc_lru_end(alloc, index);
 252                         continue;
 253                 }
 254
 255                 if (WARN_ON(!vma))
 256                         goto err_page_ptr_cleared;
 257
 258                 trace_binder_alloc_page_start(alloc, index);
 259                 page->page_ptr = alloc_page(GFP_KERNEL |
 260                                             __GFP_HIGHMEM |
 261                                             __GFP_ZERO);
 262                 if (!page->page_ptr) {
 263                         pr_err("%d: binder_alloc_buf failed for page at %pK\n",
 264                                 alloc->pid, page_addr);
 265                         goto err_alloc_page_failed;
 266                 }
 267                 page->alloc = alloc;
 268                 INIT_LIST_HEAD(&page->lru);
 269
 270                 ret = map_kernel_range_noflush((unsigned long)page_addr,
 271                                                PAGE_SIZE, PAGE_KERNEL,
 272                                                &page->page_ptr);
 273                 flush_cache_vmap((unsigned long)page_addr,
 274                                 (unsigned long)page_addr + PAGE_SIZE);
 275                 if (ret != 1) {
 276                         pr_err("%d: binder_alloc_buf failed to map page at %pK in kernel\n",
 277                                alloc->pid, page_addr);
 278                         goto err_map_kernel_failed;
 279                 }
 280                 user_page_addr =
 281                         (uintptr_t)page_addr + alloc->user_buffer_offset;
 282                 ret = vm_insert_page(vma, user_page_addr, page[0].page_ptr);
 283                 if (ret) {
 284                         pr_err("%d: binder_alloc_buf failed to map page at %lx in userspace\n",
 285                                alloc->pid, user_page_addr);
 286                         goto err_vm_insert_page_failed;
 287                 }
 288
 289                 if (index + 1 > alloc->pages_high)
 290                         alloc->pages_high = index + 1;
 291
 292                 trace_binder_alloc_page_end(alloc, index);
 293                 /* vm_insert_page does not seem to increment the refcount */
 294         }
 295         if (mm) {
 296                 up_read(&mm->mmap_sem);
 297                 mmput(mm);
 298         }
 299         return 0;
 300
 301 free_range:
 302         for (page_addr = end - PAGE_SIZE; page_addr >= start;
 303              page_addr -= PAGE_SIZE) {
 304                 bool ret;
 305                 size_t index;
 306
 307                 index = (page_addr - alloc->buffer) / PAGE_SIZE;
 308                 page = &alloc->pages[index];
 309
 310                 trace_binder_free_lru_start(alloc, index);
 311
 312                 ret = list_lru_add(&binder_alloc_lru, &page->lru);
 313                 WARN_ON(!ret);
 314
 315                 trace_binder_free_lru_end(alloc, index);
 316                 continue;
 317
 318 err_vm_insert_page_failed:
 319                 unmap_kernel_range((unsigned long)page_addr, PAGE_SIZE);
 320 err_map_kernel_failed:
 321                 __free_page(page->page_ptr);
 322                 page->page_ptr = NULL;
 323 err_alloc_page_failed:
 324 err_page_ptr_cleared:
 325                 ;
 326         }
 327 err_no_vma:
 328         if (mm) {
 329                 up_read(&mm->mmap_sem);
 330                 mmput(mm);
 331         }
 332         return vma ? -ENOMEM : -ESRCH;
 333 }
 334
 335 static struct binder_buffer *binder_alloc_new_buf_locked(
 336                                 struct binder_alloc *alloc,
 337                                 size_t data_size,
 338                                 size_t offsets_size,
 339                                 size_t extra_buffers_size,
 340                                 int is_async)
 341 {
 342         struct rb_node *n = alloc->free_buffers.rb_node;
 343         struct binder_buffer *buffer;
 344         size_t buffer_size;
 345         struct rb_node *best_fit = NULL;
 346         void *has_page_addr;
 347         void *end_page_addr;
 348         size_t size, data_offsets_size;
 349         int ret;
 350
 351         if (alloc->vma == NULL) {
 352                 binder_alloc_debug(BINDER_DEBUG_USER_ERROR,
 353                                    "%d: binder_alloc_buf, no vma\n",
 354                                    alloc->pid);
 355                 return ERR_PTR(-ESRCH);
 356         }
 357
 358         data_offsets_size = ALIGN(data_size, sizeof(void *)) +
 359                 ALIGN(offsets_size, sizeof(void *));
 360
 361         if (data_offsets_size < data_size || data_offsets_size < offsets_size) {
 362                 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
 363                                 "%d: got transaction with invalid size %zd-%zd\n",
 364                                 alloc->pid, data_size, offsets_size);
 365                 return ERR_PTR(-EINVAL);
 366         }
 367         size = data_offsets_size + ALIGN(extra_buffers_size, sizeof(void *));
 368         if (size < data_offsets_size || size < extra_buffers_size) {
 369                 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
 370                                 "%d: got transaction with invalid extra_buffers_size %zd\n",
 371                                 alloc->pid, extra_buffers_size);
 372                 return ERR_PTR(-EINVAL);
 373         }
 374         if (is_async &&
 375             alloc->free_async_space < size + sizeof(struct binder_buffer)) {
 376                 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
 377                              "%d: binder_alloc_buf size %zd failed, no async space left\n",
 378                               alloc->pid, size);
 379                 return ERR_PTR(-ENOSPC);
 380         }
 381
 382         /* Pad 0-size buffers so they get assigned unique addresses */
 383         size = max(size, sizeof(void *));
 384
 385         while (n) {
 386                 buffer = rb_entry(n, struct binder_buffer, rb_node);
 387                 BUG_ON(!buffer->free);
 388                 buffer_size = binder_alloc_buffer_size(alloc, buffer);
 389
 390                 if (size < buffer_size) {
 391                         best_fit = n;
 392                         n = n->rb_left;
 393                 } else if (size > buffer_size)
 394                         n = n->rb_right;
 395                 else {
 396                         best_fit = n;
 397                         break;
 398                 }
 399         }
 400         if (best_fit == NULL) {
 401                 size_t allocated_buffers = 0;
 402                 size_t largest_alloc_size = 0;
 403                 size_t total_alloc_size = 0;
 404                 size_t free_buffers = 0;
 405                 size_t largest_free_size = 0;
 406                 size_t total_free_size = 0;
 407
 408                 for (n = rb_first(&alloc->allocated_buffers); n != NULL;
 409                      n = rb_next(n)) {
 410                         buffer = rb_entry(n, struct binder_buffer, rb_node);
 411                         buffer_size = binder_alloc_buffer_size(alloc, buffer);
 412                         allocated_buffers++;
 413                         total_alloc_size += buffer_size;
 414                         if (buffer_size > largest_alloc_size)
 415                                 largest_alloc_size = buffer_size;
 416                 }
 417                 for (n = rb_first(&alloc->free_buffers); n != NULL;
 418                      n = rb_next(n)) {
 419                         buffer = rb_entry(n, struct binder_buffer, rb_node);
 420                         buffer_size = binder_alloc_buffer_size(alloc, buffer);
 421                         free_buffers++;
 422                         total_free_size += buffer_size;
 423                         if (buffer_size > largest_free_size)
 424                                 largest_free_size = buffer_size;
 425                 }
 426                 binder_alloc_debug(BINDER_DEBUG_USER_ERROR,
 427                                    "%d: binder_alloc_buf size %zd failed, no address space\n",
 428                                    alloc->pid, size);
 429                 binder_alloc_debug(BINDER_DEBUG_USER_ERROR,
 430                                    "allocated: %zd (num: %zd largest: %zd), free: %zd (num: %zd largest: %zd)\n",
 431                                    total_alloc_size, allocated_buffers,
 432                                    largest_alloc_size, total_free_size,
 433                                    free_buffers, largest_free_size);
 434                 return ERR_PTR(-ENOSPC);
 435         }
 436         if (n == NULL) {
 437                 buffer = rb_entry(best_fit, struct binder_buffer, rb_node);
 438                 buffer_size = binder_alloc_buffer_size(alloc, buffer);
 439         }
 440
 441         binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
 442                      "%d: binder_alloc_buf size %zd got buffer %pK size %zd\n",
 443                       alloc->pid, size, buffer, buffer_size);
 444
 445         has_page_addr =
 446                 (void *)(((uintptr_t)buffer->data + buffer_size) & PAGE_MASK);
 447         WARN_ON(n && buffer_size != size);
 448         end_page_addr =
 449                 (void *)PAGE_ALIGN((uintptr_t)buffer->data + size);
 450         if (end_page_addr > has_page_addr)
 451                 end_page_addr = has_page_addr;
 452         ret = binder_update_page_range(alloc, 1,
 453             (void *)PAGE_ALIGN((uintptr_t)buffer->data), end_page_addr);
 454         if (ret)
 455                 return ERR_PTR(ret);
 456
 457         if (buffer_size != size) {
 458                 struct binder_buffer *new_buffer;
 459
 460                 new_buffer = kzalloc(sizeof(*buffer), GFP_KERNEL);
 461                 if (!new_buffer) {
 462                         pr_err("%s: %d failed to alloc new buffer struct\n",
 463                                __func__, alloc->pid);
 464                         goto err_alloc_buf_struct_failed;
 465                 }
 466                 new_buffer->data = (u8 *)buffer->data + size;
 467                 list_add(&new_buffer->entry, &buffer->entry);
 468                 new_buffer->free = 1;
 469                 binder_insert_free_buffer(alloc, new_buffer);
 470         }
 471
 472         rb_erase(best_fit, &alloc->free_buffers);
 473         buffer->free = 0;
 474         buffer->free_in_progress = 0;
 475         binder_insert_allocated_buffer_locked(alloc, buffer);
 476         binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
 477                      "%d: binder_alloc_buf size %zd got %pK\n",
 478                       alloc->pid, size, buffer);
 479         buffer->data_size = data_size;
 480         buffer->offsets_size = offsets_size;
 481         buffer->async_transaction = is_async;
 482         buffer->extra_buffers_size = extra_buffers_size;
 483         if (is_async) {
 484                 alloc->free_async_space -= size + sizeof(struct binder_buffer);
 485                 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC_ASYNC,
 486                              "%d: binder_alloc_buf size %zd async free %zd\n",
 487                               alloc->pid, size, alloc->free_async_space);
 488         }
 489         return buffer;
 490
 491 err_alloc_buf_struct_failed:
 492         binder_update_page_range(alloc, 0,
 493                                  (void *)PAGE_ALIGN((uintptr_t)buffer->data),
 494                                  end_page_addr);
 495         return ERR_PTR(-ENOMEM);
 496 }
 497
 498 /**
 499  * binder_alloc_new_buf() - Allocate a new binder buffer
 500  * @alloc:              binder_alloc for this proc
 501  * @data_size:          size of user data buffer
 502  * @offsets_size:       user specified buffer offset
 503  * @extra_buffers_size: size of extra space for meta-data (eg, security context)
 504  * @is_async:           buffer for async transaction
 505  *
 506  * Allocate a new buffer given the requested sizes. Returns
 507  * the kernel version of the buffer pointer. The size allocated
 508  * is the sum of the three given sizes (each rounded up to
 509  * pointer-sized boundary)
 510  *
 511  * Return:      The allocated buffer or %NULL if error
 512  */
 513 struct binder_buffer *binder_alloc_new_buf(struct binder_alloc *alloc,
 514                                            size_t data_size,
 515                                            size_t offsets_size,
 516                                            size_t extra_buffers_size,
 517                                            int is_async)
 518 {
 519         struct binder_buffer *buffer;
 520
 521         mutex_lock(&alloc->mutex);
 522         buffer = binder_alloc_new_buf_locked(alloc, data_size, offsets_size,
 523                                              extra_buffers_size, is_async);
 524         mutex_unlock(&alloc->mutex);
 525         return buffer;
 526 }
 527
 528 static void *buffer_start_page(struct binder_buffer *buffer)
 529 {
 530         return (void *)((uintptr_t)buffer->data & PAGE_MASK);
 531 }
 532
 533 static void *prev_buffer_end_page(struct binder_buffer *buffer)
 534 {
 535         return (void *)(((uintptr_t)(buffer->data) - 1) & PAGE_MASK);
 536 }
 537
 538 static void binder_delete_free_buffer(struct binder_alloc *alloc,
 539                                       struct binder_buffer *buffer)
 540 {
 541         struct binder_buffer *prev, *next = NULL;
 542         bool to_free = true;
 543         BUG_ON(alloc->buffers.next == &buffer->entry);
 544         prev = binder_buffer_prev(buffer);
 545         BUG_ON(!prev->free);
 546         if (prev_buffer_end_page(prev) == buffer_start_page(buffer)) {
 547                 to_free = false;
 548                 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
 549                                    "%d: merge free, buffer %pK share page with %pK\n",
 550                                    alloc->pid, buffer->data, prev->data);
 551         }
 552
 553         if (!list_is_last(&buffer->entry, &alloc->buffers)) {
 554                 next = binder_buffer_next(buffer);
 555                 if (buffer_start_page(next) == buffer_start_page(buffer)) {
 556                         to_free = false;
 557                         binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
 558                                            "%d: merge free, buffer %pK share page with %pK\n",
 559                                            alloc->pid,
 560                                            buffer->data,
 561                                            next->data);
 562                 }
 563         }
 564
 565         if (PAGE_ALIGNED(buffer->data)) {
 566                 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
 567                                    "%d: merge free, buffer start %pK is page aligned\n",
 568                                    alloc->pid, buffer->data);
 569                 to_free = false;
 570         }
 571
 572         if (to_free) {
 573                 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
 574                                    "%d: merge free, buffer %pK do not share page with %pK or %pK\n",
 575                                    alloc->pid, buffer->data,
 576                                    prev->data, next ? next->data : NULL);
 577                 binder_update_page_range(alloc, 0, buffer_start_page(buffer),
 578                                          buffer_start_page(buffer) + PAGE_SIZE);
 579         }
 580         list_del(&buffer->entry);
 581         kfree(buffer);
 582 }
 583
 584 static void binder_free_buf_locked(struct binder_alloc *alloc,
 585                                    struct binder_buffer *buffer)
 586 {
 587         size_t size, buffer_size;
 588
 589         buffer_size = binder_alloc_buffer_size(alloc, buffer);
 590
 591         size = ALIGN(buffer->data_size, sizeof(void *)) +
 592                 ALIGN(buffer->offsets_size, sizeof(void *)) +
 593                 ALIGN(buffer->extra_buffers_size, sizeof(void *));
 594
 595         binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
 596                      "%d: binder_free_buf %pK size %zd buffer_size %zd\n",
 597                       alloc->pid, buffer, size, buffer_size);
 598
 599         BUG_ON(buffer->free);
 600         BUG_ON(size > buffer_size);
 601         BUG_ON(buffer->transaction != NULL);
 602         BUG_ON(buffer->data < alloc->buffer);
 603         BUG_ON(buffer->data > alloc->buffer + alloc->buffer_size);
 604
 605         if (buffer->async_transaction) {
 606                 alloc->free_async_space += size + sizeof(struct binder_buffer);
 607
 608                 binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC_ASYNC,
 609                              "%d: binder_free_buf size %zd async free %zd\n",
 610                               alloc->pid, size, alloc->free_async_space);
 611         }
 612
 613         binder_update_page_range(alloc, 0,
 614                 (void *)PAGE_ALIGN((uintptr_t)buffer->data),
 615                 (void *)(((uintptr_t)buffer->data + buffer_size) & PAGE_MASK));
 616
 617         rb_erase(&buffer->rb_node, &alloc->allocated_buffers);
 618         buffer->free = 1;
 619         if (!list_is_last(&buffer->entry, &alloc->buffers)) {
 620                 struct binder_buffer *next = binder_buffer_next(buffer);
 621
 622                 if (next->free) {
 623                         rb_erase(&next->rb_node, &alloc->free_buffers);
 624                         binder_delete_free_buffer(alloc, next);
 625                 }
 626         }
 627         if (alloc->buffers.next != &buffer->entry) {
 628                 struct binder_buffer *prev = binder_buffer_prev(buffer);
 629
 630                 if (prev->free) {
 631                         binder_delete_free_buffer(alloc, buffer);
 632                         rb_erase(&prev->rb_node, &alloc->free_buffers);
 633                         buffer = prev;
 634                 }
 635         }
 636         binder_insert_free_buffer(alloc, buffer);
 637 }
 638
 639 /**
 640  * binder_alloc_free_buf() - free a binder buffer
 641  * @alloc:      binder_alloc for this proc
 642  * @buffer:     kernel pointer to buffer
 643  *
 644  * Free the buffer allocated via binder_alloc_new_buffer()
 645  */
 646 void binder_alloc_free_buf(struct binder_alloc *alloc,
 647                             struct binder_buffer *buffer)
 648 {
 649         mutex_lock(&alloc->mutex);
 650         binder_free_buf_locked(alloc, buffer);
 651         mutex_unlock(&alloc->mutex);
 652 }
 653
 654 /**
 655  * binder_alloc_mmap_handler() - map virtual address space for proc
 656  * @alloc:      alloc structure for this proc
 657  * @vma:        vma passed to mmap()
 658  *
 659  * Called by binder_mmap() to initialize the space specified in
 660  * vma for allocating binder buffers
 661  *
 662  * Return:
 663  *      0 = success
 664  *      -EBUSY = address space already mapped
 665  *      -ENOMEM = failed to map memory to given address space
 666  */
 667 int binder_alloc_mmap_handler(struct binder_alloc *alloc,
 668                               struct vm_area_struct *vma)
 669 {
 670         int ret;
 671         struct vm_struct *area;
 672         const char *failure_string;
 673         struct binder_buffer *buffer;
 674
 675         mutex_lock(&binder_alloc_mmap_lock);
 676         if (alloc->buffer) {
 677                 ret = -EBUSY;
 678                 failure_string = "already mapped";
 679                 goto err_already_mapped;
 680         }
 681
 682         area = get_vm_area(vma->vm_end - vma->vm_start, VM_ALLOC);
 683         if (area == NULL) {
 684                 ret = -ENOMEM;
 685                 failure_string = "get_vm_area";
 686                 goto err_get_vm_area_failed;
 687         }
 688         alloc->buffer = area->addr;
 689         alloc->user_buffer_offset =
 690                 vma->vm_start - (uintptr_t)alloc->buffer;
 691         mutex_unlock(&binder_alloc_mmap_lock);
 692
 693 #ifdef CONFIG_CPU_CACHE_VIPT
 694         if (cache_is_vipt_aliasing()) {
 695                 while (CACHE_COLOUR(
 696                                 (vma->vm_start ^ (uint32_t)alloc->buffer))) {
 697                         pr_info("%s: %d %lx-%lx maps %pK bad alignment\n",
 698                                 __func__, alloc->pid, vma->vm_start,
 699                                 vma->vm_end, alloc->buffer);
 700                         vma->vm_start += PAGE_SIZE;
 701                 }
 702         }
 703 #endif
 704         alloc->pages = kcalloc((vma->vm_end - vma->vm_start) / PAGE_SIZE,
 705                                sizeof(alloc->pages[0]),
 706                                GFP_KERNEL);
 707         if (alloc->pages == NULL) {
 708                 ret = -ENOMEM;
 709                 failure_string = "alloc page array";
 710                 goto err_alloc_pages_failed;
 711         }
 712         alloc->buffer_size = vma->vm_end - vma->vm_start;
 713
 714         buffer = kzalloc(sizeof(*buffer), GFP_KERNEL);
 715         if (!buffer) {
 716                 ret = -ENOMEM;
 717                 failure_string = "alloc buffer struct";
 718                 goto err_alloc_buf_struct_failed;
 719         }
 720
 721         buffer->data = alloc->buffer;
 722         list_add(&buffer->entry, &alloc->buffers);
 723         buffer->free = 1;
 724         binder_insert_free_buffer(alloc, buffer);
 725         alloc->free_async_space = alloc->buffer_size / 2;
 726         barrier();
 727         alloc->vma = vma;
 728         alloc->vma_vm_mm = vma->vm_mm;
 729         mmgrab(alloc->vma_vm_mm);
 730
 731         return 0;
 732
 733 err_alloc_buf_struct_failed:
 734         kfree(alloc->pages);
 735         alloc->pages = NULL;
 736 err_alloc_pages_failed:
 737         mutex_lock(&binder_alloc_mmap_lock);
 738         vfree(alloc->buffer);
 739         alloc->buffer = NULL;
 740 err_get_vm_area_failed:
 741 err_already_mapped:
 742         mutex_unlock(&binder_alloc_mmap_lock);
 743         binder_alloc_debug(BINDER_DEBUG_USER_ERROR,
 744                            "%s: %d %lx-%lx %s failed %d\n", __func__,
 745                            alloc->pid, vma->vm_start, vma->vm_end,
 746                            failure_string, ret);
 747         return ret;
 748 }
 749
 750
 751 void binder_alloc_deferred_release(struct binder_alloc *alloc)
 752 {
 753         struct rb_node *n;
 754         int buffers, page_count;
 755         struct binder_buffer *buffer;
 756
 757         BUG_ON(alloc->vma);
 758
 759         buffers = 0;
 760         mutex_lock(&alloc->mutex);
 761         while ((n = rb_first(&alloc->allocated_buffers))) {
 762                 buffer = rb_entry(n, struct binder_buffer, rb_node);
 763
 764                 /* Transaction should already have been freed */
 765                 BUG_ON(buffer->transaction);
 766
 767                 binder_free_buf_locked(alloc, buffer);
 768                 buffers++;
 769         }
 770
 771         while (!list_empty(&alloc->buffers)) {
 772                 buffer = list_first_entry(&alloc->buffers,
 773                                           struct binder_buffer, entry);
 774                 WARN_ON(!buffer->free);
 775
 776                 list_del(&buffer->entry);
 777                 WARN_ON_ONCE(!list_empty(&alloc->buffers));
 778                 kfree(buffer);
 779         }
 780
 781         page_count = 0;
 782         if (alloc->pages) {
 783                 int i;
 784
 785                 for (i = 0; i < alloc->buffer_size / PAGE_SIZE; i++) {
 786                         void *page_addr;
 787                         bool on_lru;
 788
 789                         if (!alloc->pages[i].page_ptr)
 790                                 continue;
 791
 792                         on_lru = list_lru_del(&binder_alloc_lru,
 793                                               &alloc->pages[i].lru);
 794                         page_addr = alloc->buffer + i * PAGE_SIZE;
 795                         binder_alloc_debug(BINDER_DEBUG_BUFFER_ALLOC,
 796                                      "%s: %d: page %d at %pK %s\n",
 797                                      __func__, alloc->pid, i, page_addr,
 798                                      on_lru ? "on lru" : "active");
 799                         unmap_kernel_range((unsigned long)page_addr, PAGE_SIZE);
 800                         __free_page(alloc->pages[i].page_ptr);
 801                         page_count++;
 802                 }
 803                 kfree(alloc->pages);
 804                 vfree(alloc->buffer);
 805         }
 806         mutex_unlock(&alloc->mutex);
 807         if (alloc->vma_vm_mm)
 808                 mmdrop(alloc->vma_vm_mm);
 809
 810         binder_alloc_debug(BINDER_DEBUG_OPEN_CLOSE,
 811                      "%s: %d buffers %d, pages %d\n",
 812                      __func__, alloc->pid, buffers, page_count);
 813 }
 814
 815 static void print_binder_buffer(struct seq_file *m, const char *prefix,
 816                                 struct binder_buffer *buffer)
 817 {
 818         seq_printf(m, "%s %d: %pK size %zd:%zd:%zd %s\n",
 819                    prefix, buffer->debug_id, buffer->data,
 820                    buffer->data_size, buffer->offsets_size,
 821                    buffer->extra_buffers_size,
 822                    buffer->transaction ? "active" : "delivered");
 823 }
 824
 825 /**
 826  * binder_alloc_print_allocated() - print buffer info
 827  * @m:     seq_file for output via seq_printf()
 828  * @alloc: binder_alloc for this proc
 829  *
 830  * Prints information about every buffer associated with
 831  * the binder_alloc state to the given seq_file
 832  */
 833 void binder_alloc_print_allocated(struct seq_file *m,
 834                                   struct binder_alloc *alloc)
 835 {
 836         struct rb_node *n;
 837
 838         mutex_lock(&alloc->mutex);
 839         for (n = rb_first(&alloc->allocated_buffers); n != NULL; n = rb_next(n))
 840                 print_binder_buffer(m, "  buffer",
 841                                     rb_entry(n, struct binder_buffer, rb_node));
 842         mutex_unlock(&alloc->mutex);
 843 }
 844
 845 /**
 846  * binder_alloc_print_pages() - print page usage
 847  * @m:     seq_file for output via seq_printf()
 848  * @alloc: binder_alloc for this proc
 849  */
 850 void binder_alloc_print_pages(struct seq_file *m,
 851                               struct binder_alloc *alloc)
 852 {
 853         struct binder_lru_page *page;
 854         int i;
 855         int active = 0;
 856         int lru = 0;
 857         int free = 0;
 858
 859         mutex_lock(&alloc->mutex);
 860         for (i = 0; i < alloc->buffer_size / PAGE_SIZE; i++) {
 861                 page = &alloc->pages[i];
 862                 if (!page->page_ptr)
 863                         free++;
 864                 else if (list_empty(&page->lru))
 865                         active++;
 866                 else
 867                         lru++;
 868         }
 869         mutex_unlock(&alloc->mutex);
 870         seq_printf(m, "  pages: %d:%d:%d\n", active, lru, free);
 871         seq_printf(m, "  pages high watermark: %zu\n", alloc->pages_high);
 872 }
 873
 874 /**
 875  * binder_alloc_get_allocated_count() - return count of buffers
 876  * @alloc: binder_alloc for this proc
 877  *
 878  * Return: count of allocated buffers
 879  */
 880 int binder_alloc_get_allocated_count(struct binder_alloc *alloc)
 881 {
 882         struct rb_node *n;
 883         int count = 0;
 884
 885         mutex_lock(&alloc->mutex);
 886         for (n = rb_first(&alloc->allocated_buffers); n != NULL; n = rb_next(n))
 887                 count++;
 888         mutex_unlock(&alloc->mutex);
 889         return count;
 890 }
 891
 892
 893 /**
 894  * binder_alloc_vma_close() - invalidate address space
 895  * @alloc: binder_alloc for this proc
 896  *
 897  * Called from binder_vma_close() when releasing address space.
 898  * Clears alloc->vma to prevent new incoming transactions from
 899  * allocating more buffers.
 900  */
 901 void binder_alloc_vma_close(struct binder_alloc *alloc)
 902 {
 903         WRITE_ONCE(alloc->vma, NULL);
 904 }
 905
 906 /**
 907  * binder_alloc_free_page() - shrinker callback to free pages
 908  * @item:   item to free
 909  * @lock:   lock protecting the item
 910  * @cb_arg: callback argument
 911  *
 912  * Called from list_lru_walk() in binder_shrink_scan() to free
 913  * up pages when the system is under memory pressure.
 914  */
 915 enum lru_status binder_alloc_free_page(struct list_head *item,
 916                                        struct list_lru_one *lru,
 917                                        spinlock_t *lock,
 918                                        void *cb_arg)
 919 {
 920         struct mm_struct *mm = NULL;
 921         struct binder_lru_page *page = container_of(item,
 922                                                     struct binder_lru_page,
 923                                                     lru);
 924         struct binder_alloc *alloc;
 925         uintptr_t page_addr;
 926         size_t index;
 927         struct vm_area_struct *vma;
 928
 929         alloc = page->alloc;
 930         if (!mutex_trylock(&alloc->mutex))
 931                 goto err_get_alloc_mutex_failed;
 932
 933         if (!page->page_ptr)
 934                 goto err_page_already_freed;
 935
 936         index = page - alloc->pages;
 937         page_addr = (uintptr_t)alloc->buffer + index * PAGE_SIZE;
 938         vma = alloc->vma;
 939         if (vma) {
 940                 if (!mmget_not_zero(alloc->vma_vm_mm))
 941                         goto err_mmget;
 942                 mm = alloc->vma_vm_mm;
 943                 if (!down_write_trylock(&mm->mmap_sem))
 944                         goto err_down_write_mmap_sem_failed;
 945         }
 946
 947         list_lru_isolate(lru, item);
 948         spin_unlock(lock);
 949
 950         if (vma) {
 951                 trace_binder_unmap_user_start(alloc, index);
 952
 953                 zap_page_range(vma,
 954                                page_addr + alloc->user_buffer_offset,
 955                                PAGE_SIZE);
 956
 957                 trace_binder_unmap_user_end(alloc, index);
 958
 959                 up_write(&mm->mmap_sem);
 960                 mmput(mm);
 961         }
 962
 963         trace_binder_unmap_kernel_start(alloc, index);
 964
 965         unmap_kernel_range(page_addr, PAGE_SIZE);
 966         __free_page(page->page_ptr);
 967         page->page_ptr = NULL;
 968
 969         trace_binder_unmap_kernel_end(alloc, index);
 970
 971         spin_lock(lock);
 972         mutex_unlock(&alloc->mutex);
 973         return LRU_REMOVED_RETRY;
 974
 975 err_down_write_mmap_sem_failed:
 976         mmput_async(mm);
 977 err_mmget:
 978 err_page_already_freed:
 979         mutex_unlock(&alloc->mutex);
 980 err_get_alloc_mutex_failed:
 981         return LRU_SKIP;
 982 }
 983
 984 static unsigned long
 985 binder_shrink_count(struct shrinker *shrink, struct shrink_control *sc)
 986 {
 987         unsigned long ret = list_lru_count(&binder_alloc_lru);
 988         return ret;
 989 }
 990
 991 static unsigned long
 992 binder_shrink_scan(struct shrinker *shrink, struct shrink_control *sc)
 993 {
 994         unsigned long ret;
 995
 996         ret = list_lru_walk(&binder_alloc_lru, binder_alloc_free_page,
 997                             NULL, sc->nr_to_scan);
 998         return ret;
 999 }
1000
1001 static struct shrinker binder_shrinker = {
1002         .count_objects = binder_shrink_count,
1003         .scan_objects = binder_shrink_scan,
1004         .seeks = DEFAULT_SEEKS,
1005 };
1006
1007 /**
1008  * binder_alloc_init() - called by binder_open() for per-proc initialization
1009  * @alloc: binder_alloc for this proc
1010  *
1011  * Called from binder_open() to initialize binder_alloc fields for
1012  * new binder proc
1013  */
1014 void binder_alloc_init(struct binder_alloc *alloc)
1015 {
1016         alloc->pid = current->group_leader->pid;
1017         mutex_init(&alloc->mutex);
1018         INIT_LIST_HEAD(&alloc->buffers);
1019 }
1020
1021 int binder_alloc_shrinker_init(void)
1022 {
1023         int ret = list_lru_init(&binder_alloc_lru);
1024
1025         if (ret == 0) {
1026                 ret = register_shrinker(&binder_shrinker);
1027                 if (ret)
1028                         list_lru_destroy(&binder_alloc_lru);
1029         }
1030         return ret;
1031 }